How to know if you need chains.

Oregon has those signs. I don't remember seeing signs like that in other states. The most common signs are "Chains required to be carried from Nov to April" or something. In the front of the Motor Carrier Road Atlas is a sourced for road conditions for each state. Many states make the same info available somewhere online. On Oregon's Tripcheck.com it will say "chains required between Mile Marker X and Mile marker Y. Unfortunately it is listed in a long list of notices and not with some symbol on the map that is much easier to see when you need it.

 

WYDOT Travel Information Service
Here's Wyoming,look for different states 511 info.

 

I know Colorado has signs with lights on them that will be flashing if chaining is required.

 

There will be signs and/or overhead reader boards telling you if chains are required if you’re on a major route. About the only sign I can recall that isn’t cut and dry is the Idaho side of Lost Trail. The sign just says chains advised if road is snow covered or icy and they let that amber light flash all winter long until the snow melts.

 

In CA and WA, usually a guy wearing a uniform and a "Smokey Bear" hat tells you to pull over and hang iron. Back in my day, OR left it completely up to the driver, and with having grown up in a great-lakes snowbelt and having a truck with deep-siping and lugs on all my drives, I'd often head to OR to cross the mountains chain-free rather than deal with them on Snoqualmie or Donner.

 

Oregon is very weird with chains. They only tell you online of chains are required, but no one is there at the pass to tell you. Sometimes it’s not currently snowing, but the pass is messed up but you can’t check it from the bottom of the pass with no phone service. They don’t do a good job.

 

Check out SafeTravelUSA dot com.
The one stop shop for all the DOT websites for each state.

 

Do NOT count on others to tell you when you need chains. There are more than a few roads without warning systems (hwy 30 in SE Idaho is just one). Most of the time, authorities are nervous Nellies and put the chain sign up before it is needed. That’s no reason to put your life in the hands of some bureaucracy. Use the CB to talk to trucks coming your way. If the road is icy, or could be icy, hang the iron.